Abstract

We report effusive evaporation of thin films on GaAs(001) substrates in a production-type molecular-beam epitaxy system. A polycrystalline charge heated in a high-temperature effusion cell is used as the evaporation source. The structures are characterized by atomic force microscopy(AFM),Rutherford backscatteringspectroscopy(RBS), ellipsometry, and transmission electron microscopy(TEM). The films are amorphous and stoichiometric by transmission electron diffraction and RBS, respectively. Under optimal growth conditions, the film surface has a typical roughness of 2–3 Å as revealed by AFM, while the interface is atomically abrupt as confirmed by the cross-sectional TEM. Such amorphous and stoichiometric oxide paves the way for GaAs gate dielectrics applications.